Pager Background:
In the information age, paging devices or portable radio pagers are commonly used by people who need to stay in touch at all times. People wear pagers anywhere on their person that beep, vibrate, play a tune, or otherwise indicate when the person wearing the pager is being paged. The paging subscriber who is wearing a pager obtains the pager and contracts with a paging company to provide a paging service so that the service automatically signals the subscriber when a caller calls a designated telephone number (and occasionally additional codes) associated with the pager worn by the subscriber.
A typical paging system includes a paging terminal which connects to the public telephone network and one or more paging transmitters. The paging transmitters communicate to radio pagers via a radio link. When a caller calls a pager, the caller dials a designated telephone number and responds to prompts generated by the paging service. Typically, such prompts are voice synthesized instructions. In so responding, the caller usually enters the telephone number of a telephone where the caller will be available to receive a return call from the subscriber. A caller makes such an entry by pressing keys on the numeric keypad of a touch-tone telephone. The paging service forwards the caller-entered number with the page to the subscriber via radio transmission. Most often, the caller-entered number is the phone number of the telephone from which the caller is making the call to the pager.
When the pager receives the page, it signals the subscriber indicating that a page has been received and displays the caller-entered number on the pager's LCD. Usually, a pager signals by using an audible tone or quiet vibration. The subscriber then finds a nearby phone to call the displayed number to talk to the caller. Usually, subscribers are the type of people who deal in information that has a time-sensitive value. If the caller inadvertently entered the wrong number or failed to enter a number at all, the subscriber may never know who sent the page or why the page was sent. This problem may have a serious impact on the time-sensitive value of the information, which could lead to a significant loss.
Also, a pager with an alphanumeric LCD, or simply an alpha pager, can display information beyond a telephone number. The alpha pagers can display a wide variety of information transmitted by the paging services to the alpha pagers. Such information may include the caller's name and address, other telephone numbers, or perhaps a short message.
ANI Background:
Automatic Number Identification (ANI) is a telephone network feature that causes a local telephone switching system to send a caller's telephone number to other offices or to network switching systems. A caller is any activated, telephone-line connected, dialing-capable device with an assigned telephone number. A caller can be a person using a telephone, a computer using a modem, a fax machine, a burglar alarm and/or fire alarm system, etc. Caller-ID is the common name of the version of the ANI service that is available to residential customers from the local telephone company. In addition, ANI service is offered to commercial customers by long distance companies. A known use of the ANI service is the automation of the process of billing or routing a telephone call. Local Exchange Carriers use ANI for Centralized Automatic Message Accounting (CAMA), which is used to issue individual phone bills to subscribers.
The calling party station identification (i.e., telephone number associated with the caller) can be delivered either in-band, in the form of dual-tone multifrequency (DTMF) or multifrequency (MF) signals, or out-of-band, with Integrated Services Digital Network based (ISDN-based) services. Although the actual ANI transmission (or signal) format differs slightly from carrier to carrier, the basic format is KP+I+(7 or 10 digits)+ST where KP=key pulse;
I=information digit; PA1 (7 or 10 digits)=caller's telephone number; and PA1 ST=start signal.